This invention relates to an entry lock for controlled ingress and egress. More particularly, this invention relates to an entry lock for use in live animal growing and holding pens whereby a human can enter such pens and at the same time prevent ingress and egress to and from such pens. In live animal growing and holding pens it is important to insure that the animals do not get free. It is also important to prevent pets or other domestic animals from gaining entry to such a holding pen as a human enters the pen. Such an entry lock is especially important in the case of animals which are very valuable, subject to disease and/or difficult to catch.
Protective door structures are known but an entry lock such as provided by the present invention which prevents ingress and egress through a door opening while a human is entering a confined area has not been available.
For example U.S. Pat. No. 1,905,547 to Wood, issued Apr. 25, 1933, provides a protective entrance to a burglar-proof safe but does not prevent ingress and egress through the entry door opening while a human is passing through the protective entrance. U.S. Pat. No. 3,285,209 to Pace, issued Nov. 15, 1966 relates to a revolving door system which is designed to trap a fleeing criminal in a compartment sealed by rotation and locking of the revolving door. This structure does not prevent ingress and egress through the door opening while a human is gaining access to the confined area because of the several compartments in the revolving door system. U.S. Pat. No. 3,658,277 to Anderson, issued Apr. 25, 1972, relates to an aircraft anti-hijacking structure wherein a drum rotates to close off access to the passenger and pilot areas in an aircraft when an unauthorized person enters the drum thereby trapping such a person.